Honinbo Chihaku
Hon'inbō Chihaku (本因坊知伯, 1710–1733) was a Japanese professional go player, and sixth head of the Honinbo house.
He was a nephew of Hon'inbō Dōchi. He died young, before an official heir had been appointed.
Read more about Honinbo Chihaku: Oshirogo, Source